We’ve built many blackberry trellis over the years and this recent build is the best DIY blackberry trellis. If you want a blackberry trellis that is strong, allow for lots of air circulation, makes picking easy, and will stay tight, this is the one to build.

Cam and Becky porter standing in their newly finished blackberry trellis

Table of Contents

There are many designs available for blackberry trellises. Don’t be fooled and build an “easy” and “cheap” trellis. Speaking from experience, they don’t last and they don’t work.

Blackberry plants may start small, but they get big fast, and collectively, they can start to weigh a lot. You’ll thank yourself down the road for building a strong and sturdy trellis. Your mixed berry pie will thank you too 🙂

Keep reading to learn all the details of why a blackberry trellis is important, other types of blackberries trellises, and a step by step guide. We also have a video tutorial below.

Why Blackberries Need a Trellis

Keeps fruit off the ground: Makes picking simple and ergonomic. When blackberries are trellised the fruit is at the height of a person standing. This makes it easy to pick and easier on the body when there is a lot of picking to do.
Improves air circulation. When air circulation is good, plant leaves dry quickly. This reduces the incidences of disease.
Keeps Primocanes and Floricanes Separate You can tie the Floricanes (second year blackberry canes) to the outside of the trellis for easy picking and the primocanes (first year canes) have a place to grow.

t trellis method, in the middle of construction — This an in progress build of a T Trellis at our old home. You can see the remnants of the “cheap” first trellis we build that couldn’t handle the weight.

Types of Blackberry Trellises You Can Build at Home

There are many ways to build a blackberry trellis. Each of the types is shaped like the letter they are named after. For example a T-trellis looks like a letter “T”.

T-Trellis

Pros: The T-Trellis uses fewer line posts so there is less cost involved. Instead, it uses cross bars to hold the wires away from the posts.

Cons: A disadvantage is that it’s more difficult to adjust the height of the wires because the cross bars are stationary.

V-Trellis

Pros: A V-Trellis has two posts that are placed in the ground about 18 inches apart and angle outward, ideally the top is 42 inches wide. This shape allows lots of room for canes to grow. Floricanes are tied to the outside wires and so primocanes can grow on the inside.

Another benefit of the V trellis is the heights of the horizontal wires can be adjusted if needed. For example, we put our wires 24 inches off the ground and 48 inches off the ground. If for any reason we need to adjust those heights it would be easy to go in and move fence clips to the desired height.

Lastly, the V-trellis makes pruning blackberries very easy. In ‘V’ position, the canes are easy to see, easy to cut, and easy to pull out without too much disturbance to what remains. Check out my post on how to prune blackberries for a perfect how-to guide.

Cons: This design requires more line posts so it costs a little bit more than the T-Trellis.

finished blackberry trellis, aerial view

I-Trellis

Pros: An I trellis is basically a T-Trellis but without the cross bars. It’s low cost and easier to set up.

Cons: A HUGE disadvantage of this trellis is the wires rest directly on the line posts. It doesn’t allow a lot of space for the canes to grow. It also is known to have a reduction in yields so is not highly recommended.

So as a homegrower if you see a blackberry trellis built with a cattle panel for support or only the line posts, it’s not going to give you a good yield. Also, due to close proximity of the canes they will be more prone to disease.

Materials and Tools Needed

Tools and Supplies listed here are designed for ONE 100’ row of blackberries. Adjust quantities as needed for your project.

all the parts needed for building a 100 foot blackberry trellis

Tools:

Post Hole Digger
Power Drill
Tamping rod/stick
Wire Cutters (I used an angle grinder for the high tensile wire)
⅜” drill bit
½” drill bit
Fencing pliers
Level
A way to measure 60 degrees
Hammer
T-post fence pounder
String line
Spinning Jenny (optional but nice if doing multiple rows)

Supplies:

8 ft Treated fence posts (2)
7 ft T-posts (10)
T-post fence clips (20)
Crushed gravel for post holes
Fencing nails (2)
⅜” open eye hooks (2)
In Line Wire strainers (4)
16” screwing ground anchors (2)
12.5 gauge wire, 500ft or more
14 gauge wire, 20ft

Video Tutorial

How to Build a Blackberry Trellis Step by Step

STEP 1: Mark out areas where post holes will be dug at the end(s) of your rows. Keep in mind, the posts will stick out about 4 feet from the actual hole so allow room for mowers, tractors, weed trimmers, wheel barrows, irrigation, etc.

cam digging a hole for the blackberry trellis

STEP 2: Dig a hole at each end where you marked; 3 feet deep, at a 60 degree angle. If you have irrigation or any underground lines, ensure you don’t hit them when digging.

placing a wood post in a hole, at an angle, for holding a blackberry trellis

STEP 3: Place a 8 ft wood post in each hole. While holding the posts steady at a 60 degree angle, fill the hole around the post halfway with crushed gravel, and compact it with the tamping rod/stick. (Tip: may be useful to hire a friend to help with this part). After compacted, fill the rest of the hole with gravel and compact again. If done right, by this point the post shouldn’t move when you let go of it, and it should feel pretty tight in the hole, even at a 60 degree lean.

split photo of screwing in ground anchor on the left and pounding a fence nail on the right.

STEP 4: Screw in ground anchors and fencing nails in preparation for running the guy wire. Measure 4ft out from the post hole, and screw the ground anchor into the ground, until it’s flush with the ground. Next, using a hammer, pound the fencing nail in the top side of the wood post at roughly 4ft off the ground, leaving enough space exposed to still feed the 12.5 gauge wire through the nail hole.

three blackberry trellis end posts with guy wires attached, nice and tight.

STEP 5: Attach guy wire between wood post and the ground. Cut six feet of wire and feed the one end through this nail hole and the other end thru the ground screw. Pull the wires taut, and twist them around each other to create a secure loop that will hold under pressure. Using wire snippers, cut any excess wires off.

t posts at the end of a blackberry trellis

STEP 6: End T-posts Pound two T-posts at the beginning of the blackberry row, a few feet in from where your post hole is. The T-posts should also be pounded into the ground at an angle, At the base, the T-posts should be 18 inches apart, and when pounded in a foot or so, there should be roughly a 4 ft gap between the TOPS of the T-posts.

STEP 7: Other end T-Posts. Pound two more T posts on each side of the row at the END of the blackberry row this time, a few feet in from the post hole. The angles should match the first pair of T-posts already in the ground, or be really close.

STEP 8: Run a string line around the tops of these four T-posts, creating a “box” 5 ft up from the ground. This string line will be your reference for the rest of the T-posts and what angles they should be pounded in without having to precisely measure them each time.

STEP 9: Pound the remaining six T-posts along the row, in pairs at 25 ft increments. So in the end there will be 5 pairs of “V” posts down the blackberry rows, one pair at 0’, one pair at 25’, one at 50’, one at 75’, and the last pair at the end of the row, 100’ down. Remove the string line.

split image of drilling a hole in a fence post and twisting trellis wire around the post

STEP 10: Anchor the 100ft wires on the far post by first drilling two ½” holes thru the END post, one at 24” from the ground, and another hole at 48” from the ground. Run four 100ft wires down the sides of the rows, two on each side, Take the two wires that will be the lower trellis wires, and feed them BOTH thru the hold you just drilled. Pull enough extra wire thru that you can wrap the wire around the wood post and then twist tie the wires together. This will anchor the wires so you can tighten them with tension from the other end or the row. Repeat this with the higher trellis wires. Using wire snippers, cut any excess wire off.

closeup of t post, glove, and fence clips

STEP 11: Secure the trellis wires to the T-posts. At each T-post, measure up 24” and 48” and using T-post clips or short wires, secure the trellis wires to the T-posts. Leave them just loose enough that when tightened the wires are still able to slide back and forth as they are pulled taut.

split image of screwing an eye hook into a wood fence post and tightening the wire that is attached to the eye hook

STEP 12: Stretch/Tighten the trellis wires. At the front end of the blackberry row, drill a ⅜” hole halfway thru the wood post at 24” up and 48” up from the ground. Screw a ⅜” open ended eye bolt into each one of the holes. Slide two in line wire strainers onto each eye bolt. Push the loose ends of the four trellis lines into the corresponding wire strainers, and tighten. Walk down the line as you tighten to ensure there aren’t any kinks, snags, or other hang ups.

STEP 13: Adjust any blackberry stalks to their new trellis. Walk down the row and check for tightness and that everything is in working order. Enjoy a better crop of blackberry next season now that you have a trellis for them to grow up on.

Tips & Tricks

Bury the T-posts at least 2 feet deep in the ground so they can’t move. This is a mistake we made and had to remedy. High tensile wire will push the posts inward if they aren’t buried deep enough in the ground. You want to keep the V shape. This allows space for the primocanes to grow in the middle during the summer and the floricanes to rest on the outer edge.
Find a helper – This trellis ‘could’ be build by yourself, but there are a lot of steps that go way smoother with additional help, and…you have someone to talk to 🙂
Make sure that the In-Line wire tensioners are facing the “out” so that you can tighten them. If you do them the wrong way, the part the pliers grabs to will be on the inside, inaccessible.
When tightening the long trellis wires, tighten them all to about 80%, then rotate tightening them each a little at a time. This will allow lines to tighten evenly and will avoid sudden shifts and movement due to overtightening.
If your flexible, schedule to do this project a day or two after a heavy rain. Holes will be easier to dig, t-posts will pound in the ground easier and your back will thank you.